1. Field of the Invention
Embodiments of the present invention generally relate to footwear, and more particularly relate to exercise related footwear.
2. Background of the Invention
Most designers of modern athletic shoes strive to make a shoe which is both stable and provides adequate cushioning to the wearer. While this endeavor has led to some successful footwear products, there is a need for an athletic shoe which actually enhances a workout.
It is popular for weightlifters to use “free weights” because the athlete must not only lift the weight but also uses other muscles to stabilize the weights at the same time. This provides for a superior workout because more muscle groups are being utilized. This same principle is recognized in the use of exercise balls. However, there is a need for footwear products which employ some of these same principles. Specifically, there is a need for footwear which have a sole geometry and material selection which allow a wearer to obtain a better workout by purposefully introducing multidimensional micro-instabilities, or “controlled instabilities” into the shoe. The wearer uses his or her muscles for stability thereby obtaining a better workout and a workout which utilizes different muscles than are normally used with a traditional shoe. The use of dynamic balancing in footwear is intended to give the wearer a better workout.
The goal of providing a better workout cannot replace the need for safety. Thus, there is a need for footwear which is comfortable, is safe and provides a better workout.
The human foot is a complex and remarkable piece of machinery, capable of withstanding and dissipating many impact forces. The natural padding of fat at the heel and forefoot, as well as the flexibility of the arch, help to cushion the foot.
An athlete's stride is partly the result of energy which is stored in the flexible tissues of the foot. For example, a typical gait cycle for running or walking begins with a “heel strike” and ends with a “toe-off”. During the gait cycle, the main distribution of forces on the foot begins adjacent to the lateral side of the heel (outside of the foot) during the “heel strike” phase of the gait, then moves toward the center axis of the foot in the arch area, and then moves to the medial side of the forefoot area (inside of the foot) during “toe-off”. During a typical walking or running stride, the Achilles tendon and the arch stretch and contract, storing and releasing energy in the tendons and ligaments. When the restrictive pressure on these elements is released, the stored energy is also released, thereby reducing the burden which must be assumed by the muscles.
Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during athletic activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with athletic activity is more acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further athletic activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters, muscle, tendon and ligament damage, and bone stress fractures. Improper footwear can also lead to other ailments, including back pain. One need is for footwear which both provides protection as well as controlled instability in multiple directions.
Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole (typically including an outsole, midsole and insole) which absorbs shocks. However, the sole should also possess enough resiliency to prevent the sole from being “mushy” or “collapsing,” thereby unduly draining the stored energy of the wearer.
In light of the above, numerous attempts have been made to incorporate into a shoe improved cushioning and resiliency. For example, attempts have been made to enhance the natural resiliency and energy return of the foot by providing shoes with soles which store energy during compression and return energy during expansion. These attempts have included the formation of shoe soles that include springs, gels or foams such as ethylene vinyl acetate (EVA) or polyurethane (PU). However, all of these tend to either break down over time or do not provide adequate cushioning characteristics.
Another concept practiced in the footwear industry to improve cushioning and energy return has been the use of fluid-filled systems within shoe soles. These devices attempt to enhance cushioning and energy return by transferring a pressurized fluid between the heel and forefoot areas of a shoe. The basic concept of these devices is to have cushions containing pressurized fluid disposed adjacent the heel and forefoot areas of a shoe.
While wearing footwear with appropriate cushioning and support can help to minimize injuries, individuals can further limit injuries and improve their overall physical conditioning by participating in a regular exercise program. There are many activities in daily life that require individuals to use their strength, agility, and balance, and maintaining physical fitness can help individuals complete these activities with minimum disruption to their lives. Maintaining physical fitness has also been shown to strengthen the heart, boost HDL cholesterol, aid the circulatory system, and lower blood pressure and blood fats, translating to lower risk for heart disease, heart attack, and stroke. Exercise also strengthens muscles, increases flexibility, and promotes stronger bones, which can help prevent osteoporosis.
In today's society, many individuals struggle to maintain basic levels of fitness. Time is one of the main roadblocks to maintaining a consistent training program, both for the elite athlete and the individual struggling to maintain physical fitness. There is an ever-increasing amount of demand on a person's free time.
In response to these concerns, over the years companies have developed various forms of exercise equipment and training programs designed to maximize the efficiency of an individual's training. The equipment and programs often achieve the desired result—reducing the amount of time investment necessary to maintain physical fitness. However, these methods still require an individual to allocate a block of time out of the individual's schedule for a workout.
Thus, there is a need for a training aid that allows a user to incorporate a workout into his or her daily routine while minimizing the time investment required.